Benchmark atlas books are awesome! We use them daily and unfortunately, they're only made for the western states. They give so much clear detail, including public parks, campgrounds, etc. but for us with a Jeep, the backroads are clearly marked and very easy to read. They can't compare to a normal state map. If you travel the western states they are well worth it. Also, if you purchase from Amazon sometimes you'll get free shipping depending what you're buying and how much.
They also don't compare to a mapping program or GPS. We use those tools, also, but only for setting up a route. Once we're at our destination we go by Benchmark because you can get the 'whole picture' of an area. We started off using Delorme's atlas books but Benchmark is so much better. We have them for all the western states.
OP: You asked about getting the AZ one in southern Utah. I have seen them in national park bookstores/gift shops and also in local camping/hiking stores. Sometimes if you're close to a bordering state they'll carry both states but it's not a given. Best to pre-order them.